People have all kinds of different reasons for wanting to end a relationship. Sometimes they're just too busy to juggle a relationship with everything else they have going on in their lives. Sometimes they just need time to figure themselves out alone. And sometimes, people just fall out of love. But out of all the reasons why someone chooses to leave, a recent study published in the Personality and Social Psychology Bulletin found, there's one type of rejection that causes the most pain above all: being left in favor of someone else.

Researchers from Cornell University conducted a series of experiments using over 600 participants to see how comparative rejections really effect people. Each experiment was designed to purposely leave certain participants feeling like they've been rejected in favor of another person. For instance, one experiment involved one male participant and two females secretly working with the research team. All three people were placed in a room where one woman was told to solve a puzzle. As directed, she could either choose to solve the puzzle alone or with another person. Each time, she would choose to work with the other woman. Because of that, the male participants would feel "comparatively rejected" each time.

It's a fairly simple experiment, but I'm sure many of us can relate to the male participants in this situation. If you've ever been dumped for someone else, you know how bad that type of rejection can feel.

Why Being Rejected For Someone Else Hurts The Most

As the study found, rejection stings overall. But people felt the most hurt when they were rejected for someone else. Unlike any other kind of rejection, comparative rejections can leave you with an increased sense of exclusion and a decreased sense of belonging.

"Being left for someone else can stir up a batch of deeper, more complex emotions than those that occur after a simple breakup," Dr. Jacqueline Duke, psychologist with EXaholics tells Bustle. "Not only is one expected to cope with loss of the relationship, but underlying fears and feelings of abandonment are triggered by the sense of betrayal and of being replaced. This replacement leaves many people feeling like they are disposable, leading to strong feelings of inadequacy, failure, and ultimately shame."

The study also found that not receiving any sort of explanation for a rejection causes a ton of sadness as well. If they couldn't pinpoint an exact reason, they would naturally assume they were left for a third party.

"After the shock of finding that they have been replaced, individuals form false beliefs about themselves in response to the rejection as a way of trying to explain what they don’t understand," Duke says. According to her, psychologists refer to these misleading or false beliefs about yourself as cognitive distortions. "These cognitive distortions are then reinforced when the mind continues to ‘seek evidence,’ or examples of how the false thought may be true."

What To Tell Yourself If You've Been Left For Someone Else

If you've ever been dumped for someone else, it's not uncommon to feel completely down about yourself. Since there's another person involved, the distortion in your head can quickly turn ugly. But there are ways to combat those thoughts. "Instead of looking at internal attributions in regard to one’s self, people should look at the external attributions that contributed to the breakup," Duke says. So instead of telling yourself, "It's all my fault. I did it. I suck. I'm not good enough," tell yourself, “The relationship didn’t work for these reasons...”

If that doesn't work, think back on who you were before this happened. It's important to "revert back to positive cognitive beliefs you held about yourself," Duke says. Remind yourself about how funny, smart, and good natured you are. Think about all the different amazing things about yourself. "Understanding that the breakup can’t erase the life you had before it happened, will go a long way," she says.

Staying off social media and not stalking your ex are important of course, too. It's also crucial to allow yourself the time to cry it all out or talk it over with your support system. Above all, know that someone dumping you for someone else is never your fault.